A large wildfire that swept through the Gyeongsangbuk-do area is threatening the health of local residents and firefighters. This is because carcinogens included in the smoke from the wildfire can enter the respiratory system. This wildfire may also affect areas as far as Seoul or Jeju Island. Research results indicate that wildfire smoke can spread harmful substances hundreds of kilometers away.
A research team led by Professor Sarah Styler of the Department of Chemistry and Chemical Biology at McMaster University analyzed that polycyclic aromatic hydrocarbons (PAHs) emitted by wildfires can impact urban air quality up to 500 kilometers away. The study was published on Jan. 30 in the international journal "Environmental Science & Technology."
PAHs are hydrocarbons that occur when chemical fuels or organic materials are incompletely combusted, adversely affecting health. Notable examples include naphthalene, acenaphthylene, and benzo[a]pyrene. In particular, benzo[a]pyrene is deemed highly harmful, being classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). Until now, PAHs have mainly been emitted from vehicles or factories.
To analyze the impact of wildfire smoke on urban air quality, the research team conducted a long-term analysis of PAH concentrations in four western Canadian cities from 2010 to 2019. They also quantitatively distinguished the sources of PAHs. The results indicated that 18% to 40% of the average annual PAH concentration originated from wildfires. In years with large-scale wildfires, it was confirmed that up to 60% came from wildfire smoke.
Notably, the harmful substances traveled hundreds of kilometers to urban areas. In fact, a sharp increase in PAH concentrations has been repeatedly observed in Edmonton and Calgary, which are approximately 400 to 500 kilometers away from the wildfire site.
The research team also analyzed the characteristics of PAHs. Generally, high molecular weight PAHs are produced during high-temperature combustion, which are known to be more harmful to human health than low molecular weight PAHs. The study found that PAHs emitted from wildfires had a higher proportion of high molecular weight PAHs compared to typical urban emission sources. This implies that wildfire smoke is more dangerous to health than urban air pollution.
The findings from Canada have significant implications for South Korea as well. Following a series of wildfires that began on the 21st in various regions of Gyeongbuk, experts are expressing concerns about national air pollution. A representative from the National Institute of Environmental Research's Integrated Air Quality Forecasting Center stated, "As westerly winds began on the morning of the 27th, fine dust concentrations were measured to be high even in eastern areas, which are not directly related to the fires." In some regions, the concentration of fine particulate matter (PM2.5) soared to over 300 μg/m³, far exceeding the poor air quality standard of 75 μg/m³.
The problem is that such air pollution is difficult to predict, and the response system is inadequate. Baek Gui-nam, head of the Northeast Asia and Regional Response PM2.5 Research Team at the Korea Institute of Science and Technology (KIST), noted, "Although smoke from wildfires can affect vast areas depending on the wind direction, there is still insufficient information." He added, "We need to establish a response manual that includes smoke, dust, and gases through accurate research, as well as develop practical coping methods for everyday life."
References
Environmental Science & Technology(2025), DOI : https://doi.org/10.1021/acs.est.4c09630